Process control systems, like those used in chemical, petroleum or other processes, typically include one or more process controllers communicatively coupled to one or more field devices via analog, digital or combined analog/digital buses. The field devices, which may be, for example, valves, valve positioners, switches and transmitters (e.g., temperature, pressure and flow rate sensors), perform process control functions within the process such as opening or closing valves and measuring process control parameters. The process controllers receive signals indicative of process measurements made by the field devices and then process this information to generate control signals to implement control routines, to make other process control decisions, and to initiate process control system alarms.
Information from the field devices and/or the controller is usually made available over a data highway or communication network to one or more other hardware devices, such as operator workstations, personal computers, data historians, report generators, centralized databases, etc. Such devices are typically located in control rooms and/or other locations remotely situated relative to the harsher plant environment. These hardware devices, for example, run applications that enable an operator to perform any of a variety of functions with respect to the process of a process control system, such as viewing the current state of the process, changing an operating state, changing settings of a process control routine, modifying the operation of the process controllers and/or the field devices, viewing alarms generated by field devices and/or process controllers, simulating the operation of the process for the purpose of training personnel and/or evaluating the process, etc.
These hardware devices typically include one or more operator interface displays to display pertinent information regarding the operating state(s), condition(s), and/or characteristic(s) of the control system(s), the devices within the control system(s), and/or process variables associated with the devices in the control system(s). Example displays include piping and instrumentation diagrams (P&IDs) that represent the equipment and other components within the process control system, alarm displays that receive and/or display alarms generated by controllers or devices within the process control system, control displays that indicate the operating state(s) of the controller(s) and other device(s) within the process control system, diagnostic displays that provide detailed information regarding the current state and/or historical values for key parameters associated with components in the process control system, etc.